Positive resist composition of chemical amplification type, resist coated material, method of forming resist pattern, and process for producing semiconductor device

ABSTRACT

The present invention provides a resist composition comprising (A) polyhydroxystyrene in which at least a portion of hydrogen atoms of hydroxyl groups are substituted with an acid-dissociable dissolution inhibiting group, and the solubility in an alkali solution of the polyhydroxystyrene increasing when the acid-dissociable dissolution inhibiting group is eliminated by an action of an acid, and (B) a component capable of generating an acid by irradiation with radiation, wherein a retention rate of the acid-dissociable dissolution inhibiting group of the component (A) after a dissociation test using hydrochloric acid is 40% or less, and also provides a chemical amplification type positive resist composition which contains polyhydroxystyrene in which at least a portion of hydrogen atoms of hydroxyl groups are substituted with a lower alkoxy-alkyl group having a straight-chain or branched alkoxy group, and the solubility in an alkali solution of the polyhydroxystyrene increasing when the lower alkoxy-alkyl group is eliminated by an action of an acid, in place of the component (A).

TECHNICAL FIELD

The present invention relates to a chemical amplification type positiveresist composition which can yield a high-resolution resist patterncapable of coping with fine patterns required to the manufacture ofsemiconductor devices by a via-first dual damascene method.

BACKGROUND ART

In accordance with recent developments of higher integration ofsemiconductor devices, mass production of LSI with a design rule ofabout 0.20 μm has already started and mass production of LSIs with adesign rule of about 0.15 μm will be realized in the near future.

In addition, a chemical amplification type positive resist compositionis superior in resolution and sensitivity to a conventional non-chemicalamplification type positive resist composition using a novolak resin asa base resin and a naphthoquinonediazide sulfonate ester as aphotosensitive agent. Therefore, the conventional non-chemicalamplification type positive resist composition has recently beenreplaced by the chemical amplification type positive resist composition.

At present, it is popular to employ chemical amplification type positiveresist compositions which use, as a base resin, a copolymer or mixedresin, wherein an acetal group, which is dissociated with acomparatively weak acid, and an acid-dissociable group such astert-butoxycarbonyl group, tert-butyl group or tetrahydropyranyl group,which is not easily dissociated with a weak acid but is dissociated witha strong acid, coexist and also use a sulfonyldiazomethane acidgenerating agent as an acid generating agent (Japanese PatentApplication, First Publication No. Hei 8-15864, Japanese PatentApplication, First Publication No. Hei 8-262721, Japanese PatentApplication, First Publication No. Hei 9-160246, Japanese PatentApplication, First Publication No. Hei 9-211868, Japanese PatentApplication, First Publication No. Hei 9-274320 and Japanese PatentApplication, First Publication No. Hei 9-311452).

As prior art known before the above techniques are laid open to public,for example, there are those using a copolymer of p-(1-ethoxyethoxy)styrene and p-hydroxystyrene as a base resin and a sulfonyldiazomethaneacid generating agent such as bis (cyclohexylsulfonyl) diazomethane asan acid generating agent (Japanese Patent Application, First PublicationNo. Hei 5-249682). Such a resist composition containing a combination ofan acetal (alkoxy-alkyl) group, which is dissociated with acomparatively weak acid, as a dissolution inhibiting group and asulfonyldiazomethane compound capable of generating a weak acid forms aresist pattern having high resolution. However, the resist patternformed from the resist composition tends to narrow over time and are notsatisfactory because of insufficient heat resistance and dependence on asubstrate. Therefore, as described above, there was proposed a techniquewhose drawbacks were solved by the base resin wherein the acetal group,which is dissociated with the comparatively weak acid, and theacid-dissociable group, which is dissociated with the strong acid,coexist.

With improvements in semiconductor devices, a conventional method offorming Al wiring using a reactive ion etching (RIE) technique isalready being replaced by a method of forming Al.Cu wiring or Cu wiringusing a damascene technique in the semiconductor device manufacturingprocess.

It is expected that the damascene method will become popular in theprocess for manufacturing semiconductors of the next generation or thesubsequent generation.

In the damascene technique, a method of forming two kinds of portions tobe etched such as via holes and wiring grooves is referred to as a dualdamascene method.

In the dual damascene method, two kinds of a trench-first technique ofpreviously forming wiring grooves and a via-first technique ofpreviously forming via holes exist (“Latest Developments in Cu WiringTechniques”, pages 202 to 205, May 30, 1998, published by Realize Co.,Ltd., edited by Katsuro FUKAMI).

In the via-first method of manufacturing semiconductor devices, forexample, a base material obtained by laminating a first interlaminarinsulating layer, an etching stopper layer and a second interlaminarinsulating layer in order on a substrate is prepared. Then, a chemicalamplification type positive resist composition is applied on the basematerial and the coated base material is subjected to exposure inaccordance with a predetermined pattern, thereby to make the exposedportion alkali-soluble. The exposed portion is removed with an alkalideveloping solution and the lower layer with no resist pattern is etchedto form via holes which penetrate the first interlaminar insulatinglayer, the etching stopper layer and the second interlaminar insulatinglayer. Then, the chemical amplification type positive resist compositionis further applied and the coated one is subjected to exposure, therebyto make the exposed portion alkali-soluble. The exposed portion isremoved with an alkali developing solution and the lower layer with noresist pattern is etched to widen the groove width of the via holesformed on the second interlaminar insulating layer, thereby to formwiring grooves. Finally, copper, or copper and aluminum are embedded invia holes formed on the first interlaminar insulating layer and theetching stopper layer as well as wiring grooves formed in the secondinterlaminar insulating layer thereon, thereby to complete wiring havinggenerally T-shaped cross sectional profile.

However, the via-first dual damascene method of forming wiring groovesafter forming via holes had a drawback that resist residue is likely tobe produced in the vicinity of the upper portion (the bottom portion ofwiring grooves of the second interlaminar insulating layer) of via holesas a result of poor development when a resist pattern is formed usingthe above chemical amplification type positive resist composition usinga base resin wherein an acid-dissociable dissolution inhibiting group,which is easily dissociated with a comparatively weak acid, and anacid-dissociable dissolution inhibiting group, which is not easilydissociated with a weak acid but is dissociated with a strong acid,coexist. As a result, there arises a problem that an expected finepattern cannot be formed.

SUMMARY OF THE INVENTION

Under these circumstances, the present invention has been made, and anobject thereof is to provide a chemical amplification type positiveresist composition which can give a high-resolution resist patterncapable of coping with a fine pattern required for the manufacture ofsemiconductor devices by a via-first dual damascene method withoutproducing resist residue, a resist pattern forming method, and a methodof manufacturing a semiconductor device using the same.

The present inventors have intensively studied to achieve the aboveobject and found that a resist pattern having high resolution, highsensitivity and less resist residue can be obtained by using a chemicalamplification type positive resist composition comprisingpolyhydroxystyrene in which at least a portion of hydrogen atoms ofhydroxyl groups are substituted with an acid-dissociable dissolutioninhibiting group and a retention rate of the acid-dissociabledissolution inhibiting group after a dissociation test usinghydrochloric acid is 40% or less, and a component capable of generatingan acid by irradiation with radiation. Thus, a first chemicalamplification type positive resist composition of the present inventionhas been completed.

That is, the first chemical amplification type positive resistcomposition of the present invention comprises the following components(A) and (B):

-   (A) polyhydroxystyrene in which at least a portion of hydrogen atoms    of hydroxyl groups are substituted with an acid-dissociable    dissolution inhibiting group, and the solubility in an alkali    solution of the polyhydroxystyrene increasing when the    acid-dissociable dissolution inhibiting group is eliminated by an    action of an acid, and-   (B) a component capable of generating an acid by irradiation with    radiation, wherein

a retention rate of the acid-dissociable dissolution inhibiting group ofthe component (A) after a dissociation test using hydrochloric acid is40% or less.

Also the present inventors have found that a resist pattern havingexcellent cross sectional profile can be obtained without producingresist residue by using a chemical amplification type positive resistcomposition comprising polyhydroxystyrene in which at least a portion ofhydrogen atoms of hydroxyl groups are substituted with a loweralkoxy-alkyl group having a straight-chain or branched alkoxy group andthe lower alkoxy-alkyl group is eliminated by an action of an acid, andthe solubility in an alkali solution of the polyhydroxystyreneincreasing when elimination occurs, and a component capable ofgenerating an acid by irradiation with radiation, wherein two or morekinds of mutually different lower alkoxy-alkyl groups are used as thelower alkoxy-alkyl group of the component. Thus, the second chemicalamplification type positive resist composition of the present inventionhas been completed based on this finding.

The second chemical amplification type positive resist composition ofthe present invention comprises the following components (A) and (B):

-   (A) polyhydroxystyrene in which at least a portion of hydrogen atoms    of hydroxyl groups are substituted with a lower alkoxy-alkyl group    having a straight-chain or branched alkoxy group and the lower    alkoxy-alkyl group is eliminated by an action of an acid, and the    solubility in an alkali solution of the polyhydroxystyrene    increasing when elimination occurs, and-   (B) a component capable of generating an acid by irradiation with    radiation, wherein

two or more kinds of mutually different lower alkoxy-alkyl groups areused as the lower alkoxy-alkyl group of the component (A).

The present invention provides a resist laminated material comprising abase material obtained by laminating a first interlaminar insulatingfilm layer, an etching stopper layer and a second interlaminarinsulating layer in sequence, and a coating layer of the first or secondchemical amplification type positive resist composition provided on thebase material.

Also the present invention provides a resist pattern forming method,which comprises applying a chemical amplification type positive resistcomposition on a base material and subjecting the coated base materialto selective exposure and development in sequence to form a resistpattern, wherein

the chemical amplification type positive resist composition is the firstor second chemical amplification type positive resist composition.

Also the present invention provides a method of manufacturing asemiconductor device using a via-first dual damascene method of formingvia holes on a base material and forming wiring grooves at the upperportion, which comprises forming at least the wiring grooves by theresist pattern forming method.

DETAILED DESCRIPTION OF THE INVENTION

The chemical amplification type positive resist composition of thepresent invention will now be described in detail by way of examples.

(1) First Chemical Amplification Type Positive Resist Composition

In the present invention, as the chemical amplification type positiveresist composition, a chemical amplification type positive resistcomposition comprising:

(A) polyhydroxystyrene (base resin) in which at least a portion ofhydrogen atoms of hydroxyl groups are substituted with anacid-dissociable dissolution inhibiting group, and the solubility in analkali solution of the polyhydroxystyrene increasing when theacid-dissociable dissolution inhibiting group is eliminated by an actionof an acid, and

(B) a component capable of generating an acid by irradiation withradiation (acid generating agent) is used.

(i) Re: component (A)

The component (A) is characterized in that the retention rate of theacid-dissociable dissolution inhibiting group after a dissociation testusing hydrochloric acid is 40% or less, and preferably 30% or less.

The dissociation test using hydrochloric acid is conducted in thefollowing procedure. That is, 10 parts by weight of hydrochloric acidhaving a concentration of 10% by weight is added to 100 parts by weightof a 10 wt % propylene glycol monomethyl ether acetate solution of thecomponent (A) maintained at a liquid temperature of 23° C. and, afterstirring for 10 minutes, an acid-dissociable dissolution inhibitinggroup is dissociated. Then, the substitution rate of theacid-dissociable dissolution inhibiting group before and after an acidtreatment is measured by a ¹³C-NMR method and the retention rate isdetermined from the measured value by the following equation.${{Retention}\quad{rate}\quad(\%)} = {\frac{{substitution}\quad{rate}\quad{after}\quad{acid}\quad{treatment}}{{substitution}\quad{rate}\quad{before}\quad{acid}\quad{treatment}} \times 100}$

It is defined that the retention rate exceeds 40% in the mixture of thecomponent in which the retention rate of the acid-dissociabledissolution inhibiting group is 40% or less and the component in whichthe retention rate of the acid-dissociable dissolution inhibiting groupexceeds 40%. One, two or more kinds each having a different retentionrate can be used in combination as the component (A). However, when thecomponent in which the retention rate exceeds 40% is contained in alarge amount, resist residue cannot be prevented and, therefore, it isdisadvantageous.

Therefore, the component in which the retention rate exceeds 40% may becontained in a very small amount as far as the operation and effect ofthe present invention are not adversely affected. It is preferred thatthe component (A) be substantially composed only of the component orcomponents having the retention rate of 40% or less.

As described above, it is necessary to use the component (A) having asmall retention rate in order to prevent resist residue. Therefore, itis necessary to use the component (A) which is substantially free froman acid-dissociable dissolution inhibiting group which is dissociatedonly with a strong acid (for example, an acid-dissociable dissolutioninhibiting group which is not easily dissociated as compared with alower alkoxy-alkyl group).

As described in the BACKGROUND ART, in a chemical amplification typepositive resist composition which has conventionally been put intopractice, polyhydroxystyrene having both an acid-dissociable dissolutioninhibiting group which can be dissociated even with a comparatively weakacid and an acid-dissociable dissolution inhibiting group which isdissociated only with a strong acid was used as the base resin.

In contrast, in the present invention, the acid-dissociable dissolutioninhibiting group which is dissociated only with a strong acid issubstantially excluded. The component having the acid-dissociabledissolution inhibiting group which is dissociated only with a strongacid cannot satisfy such an essential constitution of the presentinvention that the retention rate of the acid-dissociable dissolutioninhibiting group after the dissociation test using hydrochloric acid is40% or less, and thus resist residue is likely to be produced.

The acid-dissociable dissolution inhibiting group which is dissociatedonly with a strong acid is, for example, an acid-dissociable dissolutioninhibiting group which is not easily dissociated as compared with alower alkoxy-alkyl group. Specific examples thereof include tertiaryalkyloxycarbonyl group, tertiary alkyl group and cyclic ether group.More specifically, tert-butoxycarbonyloxy group, tert-butyl group andtetrahydropyranyl group are listed.

The component (A) includes, for example, polyhydroxystyrene comprising:

(a₁) a hydroxystyrene unit, and

(a₂) a unit in which at least a portion of hydrogen atoms of hydroxylgroups of hydroxystyrene are substituted with an acid-dissociabledissolution inhibiting group and the acid-dissociable dissolutioninhibiting group is only a lower alkoxy-alkyl group, or a combination ofthe lower alkoxy-alkyl group and a group which is easily dissociated ascompared with the lower alkoxy-alkyl group.

The unit (a₁) is a unit which imparts alkali solubility and adhesion tothe substrate and is derived through cleavage of an ethylenic doublebond of hyroxystyrene or hydroxy a-methylstyrene. The position of thehydroxy group may be the o-position, m-position or p-position, and mostpreferably the p-position in view of availability and low cost.

The unit (a₂) is a portion which makes the component (A) alkali-solublefrom alkali-insoluble by exposure.

When the chemical amplification type positive resist composition appliedon the base material is irradiated with predetermined radiation, an acidis generated from an acid generating agent as the component (B) and theacid-dissociable dissolution inhibiting group of the unit (a₂) iseliminated by an action of the acid, and thus the eliminated portion isconverted into a phenolic hydroxyl group. As a result, the component(A), which was alkali-insoluble before the exposure, is made to bealkali-soluble after the exposure.

As described above, the lower alkoxy-alkyl group is a preferableacid-dissociable dissolution inhibiting group which satisfies theconstitution of the retention rate of 40% or less in the component (A).Specific examples thereof include 1-ethoxyethyl group,1-methoxy-1-methylethyl group, 1-isopropoxyethyl group, 1-methoxypropylgroup and 1-n-butoxyethyl group.

The component (A) may contain a copolymerizable unit other than theunits (a₁) and (a₂), and is preferably composed of the units (a₁) and(a₂) in view of suppression of resist residue.

The component (A) may be, for example, a resin having only a loweralkoxy-alkyl group as the acid-dissociable dissolution inhibiting group,namely, a polymer in which a portion of hydrogen atoms of hydroxylgroups of polyhydroxystyrene are substituted with only a loweralkoxy-alkyl group.

Also it may be a mixture of two or more kinds of polyhydroxystyrenes inwhich a portion of hydrogen atoms of hydroxyl groups ofpolyhydroxystyrene are substituted with different lower alkoxy-alkylgroups.

The weight-average molecular weight of the component (A) is preferablywithin a range from 3000 to 30000, and more preferably from 5000 to15000. When the weight-average molecular weight is less than 3000, theresulting composition is inferior in film-forming properties. On theother hand, when it exceeds 30000, it becomes difficult to dissolve inan alkali solution, particularly an aqueous alkali solution.

Also 10 to 60%, preferably 15 to 50%, of hydrogen atoms of hydroxylgroups in polyhydroxystyrene are preferably substituted with anacid-dissociable dissolution inhibiting group. When the proportion isless than 10%, the dissolution in the alkali solution, particularly theaqueous alkali solution, is not sufficiently suppressed. On the otherhand, when it exceeds 60%, it becomes difficult to dissolve in thealkali solution, particularly the aqueous alkali solution.

Specifically the component (A) is preferably polyhydroxystyrene having aweight-average molecular weight within a range from 3000 to 30000 and adispersion degree (number-average molecular weight/weight-averagemolecular weight) within a range from 1.0 to 6.0 in which 10 to 60% ofhydrogen atoms of hydroxyl groups of polyhydroxystyrene are substitutedwith a 1-ethoxyethyl group or 1-isopropoxyethyl group because ofexcellent resolution and excellent resist pattern profile.

Particularly, in order to prevent trailing of the resist pattern and toachieve high resolution, it is preferred to use a mixture obtained bymixing polyhydroxystyrene in which hydrogen atoms are substituted withthe 1-ethoxyethyl group and polyhydroxystyrene in which hydrogen atomsare substituted with the 1-isopropoxyethyl group in a weight ratiowithin a range from 1:9 to 9:1, and preferably from 5:5 to 1:9. Whenusing the component (A) with such a composition, the alkali solubilityis easily enhanced by irradiation with radiation and a problem such asresist residue can be accurately solved.

(ii) Re: component (B)

The component (B) is not specifically limited as long as it is capableof generating an acid by exposure. For example, a sulfonyldiazomethaneacid generating agent, an onium salt acid generating agent and an oximesulfonate acid generating agent can be used.

Examples of the onium salt acid generating agent includetrifluoromethane sulfonate or nonafluorobutane sulfonate ofbis(4-tert-butylphenyl) iodonium; trifluoromethane sulfonate ornonafluorobutane sulfonate of triphenyl sulfonium; trifluoromethanesulfonate or nonafluorobutane sulfonate of dimethylmonophenyl sulfonium;trifluoromethane sulfonate or nonafluorobutane sulfonate ofmonomethyldiphenyl sulfonium; and trifluoromethane sulfonate ornonafluorobutane sulfonate of4-tert-butoxycarbonylmethyloxyphenyldiphenyl sulfonium.

Examples of the oxime sulfonate acid generating agent include

-   a-(methylsulfonyloxyimino)-phenylacetonitrile,-   a-(methylsulfonyloxyimino)-4-methoxyphenylacetonitrile,-   a-(trifluoromethylsulfonyloxyimino)-4-methoxyphenylacetonitrile,-   a-(propylsulfonyloxyimino)-4-methylphenylacetonitrile,-   a-(methylsulfonyloxyimino)-4-bromophenylacetonitrile, and a compound    represented by the following chemical formula (1):

Examples of the sulfonyldiazomethane acid generating agent includebisalkylsulfonyldiazomethane having a straight-chain or branched alkylgroup, such as bis(n-propylsulfonyl)diazomethane,bis(isopropylsulfonyl)diazomethane, bis(n-butylsulfonyl)diazomethane,bis(isopropylsulfonyl)diazomethane andbis(tert-butylsulfonyl)diazomethane.

These components (B) may be used alone, or two or more kinds of them maybe used in combination.

Among these compounds, bisalkylsulfonyldiazomethane having astraight-chain or branched C₁₋₄ alkyl group is preferred in view of thetransparency, proper acidity and alkali solubility.

Furthermore, bis(isopropylsulfonyl)diazomethane,bis(tert-butylsulfonyl)diazomethane or a mixture thereof is preferredbecause a resist pattern having high resolution can be obtained andresist residue is suppressed.

When using bisalkylsulfonyldiazomethane as the component (B), in casethe component (B) contains bisalkylsulfonyldiazomethane as a maincomponent and further contains an onium salt in the amount within arange from 2 to 5% by weight of based on bisalkylsulfonyldiazomethane,higher resolution can be achieved and, therefore, it is preferred.

The onium salt is preferably trifluoromethane sulfonate ornonafluorobutane sulfonate of bis(4-tertbutylphenyl)iodonium.

The amount of the component (B) is within a range from 0.5 to 30 partsby weight, and preferably from 1 to 10 parts by weight, based on 100parts by weight of the component (A). When the amount is less than 0.5parts by weight, formation of the pattern is not sufficiently conductedat times. On the other hand, when the amount exceeds 30 parts by weight,it is difficult to obtain a uniform solution and the storage stabilityis likely to be lowered.

(iii) Re: other components

If necessary, the chemical amplification type positive resistcomposition can contain other components, in addition to the components(A) and (B).

Examples of the other component, which can be added, include knownadditives, for example, organic amines which exert an action ofimproving the stability over time (post-exposure stability of the latentimage formed by the pattern-wise exposure of the resist layer) andpreventing excess diffusion of the acid; organic carboxylic acids whichexert an action of improving the sensitivity of the resist composition,thereby to eliminate the dependency on the substrate; antihalationagents; and surfactants for prevention of striation.

As the organic amine, for example, a secondary or tertiary aliphaticamine such as trimethylamine, diethylamine, triethylamine,di-n-propylamine, tri-n-propylamine, tripentylamine, diethanolamine ortriethanolamine is used. Particularly, a tertiary aliphatic amine suchas trialkylamine or trialkanolamine is preferred because of highaddition effects.

These organic amines can be used alone, or two or more kinds of them canbe used in combination. The organic amine is commonly used in an amountwithin a range from 0.01 to 5% by weight based on the component (A).When the amount is less than 0.01% by weight, it is difficult to obtainthe addition effect. On the other hand, when the amount exceeds 5% byweight, the sensitivity is lowered.

As the organic carboxylic acid, for example, aliphatic carboxylic acidsuch as acetic acid, citric acid, succinic acid, malonic acid or maleicacid; and aromatic carboxylic acid such as benzoic acid or salicylicacid are used.

These organic carboxylic acids may be used alone, or two or more kindsof them may be used in combination. The organic carboxylic acid iscommonly used in the amount within a range from 0.01 to 5% by weightbased on the component (A). When the amount is less than 0.01% byweight, it is difficult to obtain the addition effect. On the otherhand, when the amount exceeds 5% by weight, the effect does notincrease.

(iv) Form of chemical amplification type positive resist compositionused to form a resist pattern

The chemical amplification type positive resist composition is used toform a resist pattern in the form of a coating solution prepared bydissolving the components (A) and (B) and optionally added additioncomponents in an organic solvent.

The organic solvent used to form the coating solution is notspecifically limited as long as it can dissolve the components (A) and(B) to form a uniform solution, and one, two or more kinds selected fromthose, which have been conventionally known as the solvent of thechemical amplification type resist, can be used.

Specific examples of the organic solvent include:

-   ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl    isoamyl ketone and 2-heptanone;-   derivatives of polyhydric alcohols, such as ethylene glycol,    ethylene glycol monoacetate, diethylene glycol, diethylene glycol    monoacetate, propylene glycol, propylene glycol monoacetate,    dipropylene glycol, and monomethyl ether, monoethyl ether,    monopropyl ether, monobutyl ether or monophenyl ether of dipropylene    glycol monoacetate;-   cyclic ethers of dioxane; and-   esters such as methyl lactate, ethyl lactate, methyl acetate, ethyl    acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl    methoxypropionate and ethyl ethoxypropionate.    (2) Second Chemical Amplification Type Positive Resist Composition

(i) Re: component (A)

As the lower alkoxy-alkyl group of the component (A), two or more kindsof mutually different lower alkoxy-alkyl groups having a straight-chainor branched alkyl group are used.

As the component (A), a mixed resin obtained by mixing two or more kindsof polyhydroxystyrenes each having a different lower alkoxy-alkyl group,or a copolymer containing two or more kinds of mutually differenthydroxystyrene units having a lower alkoxy-alkyl group can be used.

As the mixed resin, there can be used a mixture containing a firstpolyhydroxystyrene in which at least a portion of hydrogen atoms ofhydroxyl groups are substituted with a first lower alkoxy-alkyl groupand a second polyhydroxystyrene in which at least a portion of hydrogenatoms of hydroxyl groups are substituted with a second loweralkoxy-alkyl group which is different from the first lower alkoxy-alkylgroup.

As the copolymer, there can be used polyhydroxystyrene containing afirst hydroxystyrene unit in which at least a portion of hydrogen atomsof hydroxyl groups are substituted with the first lower alkoxy-alkylgroup and a second hydroxystyrene unit in which at least a portion ofhydrogen atoms of hydroxyl groups are substituted with the second loweralkoxy-alkyl group which is different from the first lower alkoxy-alkylgroup.

The alkoxy group included in the lower alkoxy-alkyl group preferably has5 or less carbon atoms, and also the alkyl group preferably has 5 orless carbon atoms.

In the component (A), in the case in which at least one kind of theselower alkoxy-alkyl groups is a lower alkoxy-alkyl group having astraight-chain alkoxy group (hereinafter an alkoxy-alkyl group having astraight-chain alkoxy group is referred to as a “straight-chainalkoxy-alkyl group”, while an alkoxy-alkyl group having a straight-chainalkoxy group being combined with carbon at the 1-position of the alkylgroup is referred to as a “1-straight-chain alkoxy-alkyl group”) and atleast one kind of other lower alkoxy-alkyl groups is a branched loweralkoxy-alkyl group (hereinafter an alkoxy-alkyl group having a branchedalkoxy group is referred to as a “branched alkoxy-alkyl group”, while analkoxy-alkyl group having a branched alkoxy group being combined withcarbon at the 1-position of the alkyl group is referred to as a“1-branched alkoxy-alkyl group”), the resist pattern profile and theresolution can be improved with good balance and, therefore, it ispreferred.

Examples of the component (A) include the mixed resin or copolymer inwhich the first lower alkoxy-alkyl group is a lower straight-chainalkoxy-alkyl group and the second lower alkoxy-alkyl group is a lowerbranched alkoxy-alkyl group.

Examples of the lower straight-chain alkoxy-alkyl group include one, twoor more kinds selected from the group consisting of 1-ethoxyethyl group,1-methoxy-1-methylethyl group, 1-methoxypropyl group and 1-n-butoxyethylgroup.

Examples of the lower branched alkoxy-alkyl group include one, two ormore kinds selected from the group consisting of 1-isopropoxyethylgroup, 1-isobutoxyethyl group and 1-sec-butoxyethyl group.

The component (A) preferably contains:

(A1) polyhydroxystyrene in which at least a portion of hydrogen atoms ofhydroxyl groups are substituted with a 1-straight-chain alkoxy-alkylgroup, and

(A2) polyhydroxystyrene in which at least a portion of hydrogen atoms ofhydroxyl groups are substituted with a 1-branched alkoxy-alkyl group.

Examples of the 1-straight-chain alkoxy-alkyl group include the samegroups as those listed as the above lower straight-chain alkoxy-alkylgroup.

Examples of the 1-branched alkoxy-alkyl group include the same groups asthose listed as the above lower branched alkoxy-alkyl group.

Examples of the polyhydroxystyrene used in the component (A) includethose containing:

(a1) a hydroxystyrene unit, and

(a2) a unit in which hydrogen atoms of hydroxyl groups of thehydroxystyrene are substituted with a lower alkoxy-alkyl group.

The unit (a1) is a unit which imparts alkali solubility and adhesion tothe substrate and is derived through cleavage of an ethylenic doublebond of or hydroxy a-methylstyrene.

The position of the hydroxyl group may be the o-position, m-position orp-position, and most preferably the p-position in view of availabilityand low cost.

The unit (a2) is a portion which makes the component (A) alkali-solublefrom alkali-insoluble by exposure.

When the chemical amplification type positive resist composition appliedon the base material is irradiated with predetermined radiation, an acidis generated from an acid generating agent as the component (B) and theacid-dissociable dissolution inhibiting group of the unit (a2) iseliminated by an action of the acid, and thus the eliminated portion isconverted into a phenolic hydroxyl group. As a result, the component(A), which was alkali-insoluble before the exposure, is made to bealkali-soluble after the exposure.

The polyhydroxystyrene used in the component (A) may contain acopolymerizable unit other than the units (a1) and (a2), and ispreferably composed of the units (a1) and (a2) in view of suppression ofresist residue.

The weight-average molecular weight of the component (A) is preferablywithin a range from 3000 to 30000, and more preferably from 5000 to15000. When the weight-average molecular weight is less than 3000, theresulting composition is inferior in film-forming properties. On theother hand, when it exceeds 30000, it becomes difficult to dissolve inan alkali solution, particularly an aqueous alkali solution.

In the component (A), 10 to 60%, preferably 15 to 50%, of hydrogen atomsof hydroxyl groups in polyhydroxystyrene are preferably substituted witheach of lower alkoxy-alkyl groups (lower alkoxy-alkyl group having astraight-chain alkoxy group and lower alkoxy-alkyl group having abranched alkoxy group). When the proportion is less than 10%, thedissolution in the alkali solution, particularly the aqueous alkalisolution, is not sufficiently suppressed. On the other hand, when itexceeds 60%, it becomes difficult to dissolve in the alkali solution,particularly the aqueous alkali solution.

The component (A) preferably contains:

(A1′) polyhydroxystyrene having a weight-average molecular weight withina range from 3000 to 30000 and a dispersion degree (number-averagemolecular weight/weight-average molecular weight) within a range from1.0 to 6.0 in which 10to 60% of hydrogen atoms of hydroxyl groups ofpolyhydroxystyrene are substituted with a 1-straight-chain alkoxy-alkylgroup (particularly 1-ethoxyethyl group), and

(A2′) polyhydroxystyrene having a weight-average molecular weight withina range from 3000 to 30000 and a dispersion degree (number-averagemolecular weight/weight-average molecular weight) within a range from1.0 to 6.0 in which 10 to 60% of hydrogen atoms of hydroxyl groups ofpolyhydroxystyrene are substituted with a 1-branched alkoxy-alkyl group(particularly 1-isopropoxyethyl group) because of excellent resolutionand excellent resist pattern profile.

When the dispersion degree exceeds 6.0, the resolution and the resistpattern profile are lowered and, therefore, it is not preferred.

In order to prevent trailing of the resist pattern and to achieve highresolution, it is preferred to use a mixture obtained by mixing (A1),namely, polyhydroxystyrene in which at least a portion of hydrogen atomsof hydroxyl groups are substituted with the 1-straight-chainalkoxy-alkyl group (particularly 1-ethoxyethyl group) with (A2), namely,polyhydroxystyrene in which at least a portion of hydrogen atoms ofhydroxyl groups are substituted with the 1-branched alkoxy-alkyl group(particularly 1-isopropoxyethyl group) in a weight ratio within a rangefrom 1:9 to 9:1, and preferably from 5:5 to 1:9.

When the mixing ratio of these two kinds of polyhydroxystyrenes deviatesfrom the above range, the resolution and the resist pattern profile arelowered and, therefore, it is not preferred.

When using the component (A) with such a composition, the alkalisolubility is easily enhanced by irradiation with radiation and aproblem such as resist residue can be accurately solved.

In the component (A), the retention rate of the acid-dissociabledissolution inhibiting group after a dissociation test usinghydrochloric acid is 40% or less, and preferably 30% or less.

When the retention rate exceeds 40%, resist residue is likely to beproduced and, therefore, it is not preferred.

The dissociation test using hydrochloric acid is defined in the samemanner as in case of the dissociation test using hydrochloric acid ofthe component (A) of the first chemical amplification type positiveresist composition.

Regarding (ii) component (B), (iii) other components, and (iv) form ofchemical amplification type positive resist composition used to form aresist pattern, almost the same descriptions as those in the case of theabove first chemical amplification type resist composition can bestated.

The first or second chemical amplification type positive resistcomposition of the present invention is suited for use in themanufacture of semiconductor devices by a via-first dual damascenemethod.

(3) Base Material

In the present invention, the base material, which is used in the resistlaminated material and is also used to form a resist pattern ispreferably composed of a substrate, and a first interlaminar insulatinglayer, an etching stopper layer and a second interlaminar insulatinglayer laminated in that order on the substrate.

As the substrate, a substrate used commonly in the manufacture ofsemiconductor devices can be used and, for example, a silicon wafer isused.

An insulating film made of a low dielectric constant material is used inthe first interlaminar insulating layer and the second interlaminarinsulating layer. As used herein, the low dielectric constant materialis preferably a material having a dielectric constant of 3.0 or lessbecause it is is used for manufacturing through the dual damascenemethod.

These first and second interlaminar insulating layers can be formed, forexample, by a CVD method, an organic or inorganic SOG method, or arotary coating method of an organic polymer.

Examples of the first and second interlaminar insulating layers includesilicon oxide layer obtained by the plasma CVD method (specifically,“BLACK DIAMOND” manufactured by Applied Materials Inc. and “CORAL”manufactured by Novellus Inc. may be mentioned); a hydrogen-containingsilicon oxide layer having a Si—H group obtained by combining silicon ofa silicon oxide layer with a hydrogen atom; polyimide film;benzocyclobutene polymer film; alkyl group-containing silicon oxide filmobtained by combining a silicon atom in a silicon oxide layer with analkyl group such as a methyl group; fluorine-containing silicon oxidelayer; fluorine base resin film; mixture film made of a silicon porousmaterial and a fluorine base resin; arylene ether polymer film; mixturefilm made of a fluorine base resin and a siloxane base resin;polyquinoline base resin film; polyquinoline base resin film; andfullerene film.

Among these films, a silicon oxide film is preferred because ofexcellent practicability.

The etching stopper layer is formed to prevent excess etching in thecase of etching wiring grooves or via holes with high accuracy.

Preferred examples of the etching stopper layer include those obtainedby forming materials such as silicon nitride (SiN), silicon carbide(SiC) or tantalum nitride (TaN) into a film by the CVD method.

The thickness of the first and second interlaminar insulating layers iswithin a range from 100 to 300 nm, and preferably from 200 to 300 nm.

The thickness of the etching stopper layer is within a range from 50 to120 nm, and preferably from 50 to 100 nm.

The base material used in the present invention can be provided with ahard mask layer made of carbo-oxidated silicon (SiOC) or silicon nitride(SiN) on the second interlaminar insulating layer according to thepurposes. When the hard mask layer is provided, the effect of preventingexcess etching can be obtained.

The thickness of the hard mask layer is within a range from 50 to 120nm, and preferably from 500 to 100 nm.

In the present invention, the following base materials can be used.

In the above base material, the etching stopper layer sometimesincreases the dielectric constants of the first and second interlaminarinsulating films provided thereon and thereunder to cause a problemaccording to the purposes. In that case, a base material obtained byproviding a single-layer structure interlaminar insulating film and thesame hard mask layer as described above on a substrate without providingthe etching stopper layer can be used. The thickness of the single-layerstructure interlaminar insulating film is within a range from 300 to 700nm, and preferably from 400 to 600 nm. The dielectric constant of theinterlaminar insulating layer is preferably 3.0 or less and theinterlaminar insulating layer is preferably made of the silicon oxidelayer because of excellent practicability.

(4) Resist Laminated Material

The resist laminated material of the present invention is obtained byapplying the first or second chemical amplification type positive resistcomposition prepared as described above on the base material to form acoating layer. The thickness of the coating layer is within a range, forexample, from 0.3 to 0.7 μm.

The laminated material is preferably a resist laminated materialobtained by providing the coating layer made of the first or secondchemical amplification type positive resist composition of the presentinvention on the base material obtained by laminating the firstinterlaminar insulating film, the etching stopper and the secondinterlaminar insulating film in sequence.

Alternatively, it can be a resist laminated material in which an organicfilm is provided between the base material and the resist coating layer.The organic film is a film formed by applying a composition for formingan organic film and exerts an effect of smoothening the base materialand preventing reflection from the base material, or serves as anetching stopper layer, as is described in detail in the following resistpattern forming method (5).

(5) Resist Pattern Forming Method

The resist pattern can be formed in the following procedure.

The resist laminated material is prepared and then heated by irradiatingwith radiation from the coating layer side through a desired maskpattern according to a normal method. Then, the exposed resist laminatedmaterial is developed using an alkali developing solution, for example,an aqueous 0.1 to 10 wt % solution of tetrahydroammonium hydroxide. As aresult, the exposed portion is dissolved in the alkali developingsolution, and thus a resist pattern faithful to a mask pattern can beformed.

As the radiation, KrF or ArF excimer laser is generally used and alsoradiation having a shorter wavelength such as an F₂ laser, EUV (extremeultraviolet light), VUV (vacuum ultraviolet light), electron beam, X-rayor soft X-ray can be used.

If necessary, an organic film can be formed before irradiation withradiation by applying the composition for forming an organic film on thebase material and under the coating layer of the chemical amplificationtype positive resist composition. The organic film is made of an organiccompound having film-forming properties and exerts the effect ofsmoothening the base material and preventing reflection from the basematerial, or serves as an etching stopper layer of a via innermost layerin the case of forming a trench.

The organic film can be formed by the following procedure. Herein, anorganic film having an ability to prevent organic reflection will bedescribed.

An amino crosslinking agent in which at least two hydrogen atoms ofamino groups are substituted with either or both of a methylol group anda lower alkoxymethyl group, for example, benzoguanamine, melamine orurea, and an acidic compound are dissolved in an organic solvent toprepare a composition for forming an anti-reflection film. The resultingcomposition for forming an anti-reflection film is applied on a basematerial, dried, and then heated at 100 to 300° C. to obtain an organicanti-reflection film.

Examples of the acidic compound include organic acid such as sulfuricacid, sulfurous acid or thiosulfuric acid; organic sulfonic acid;organic sulfonate ester; and an acid generating agent capable ofgenerating an acid by activating light.

A particularly preferred organic film to be applied to the presentinvention is formed of a composition for forming an organic film inwhich the proportion of an oligomer such as trimer, dimer, or monomer ofan amino crosslinking agent is controlled to 15% by weight or less basedon the amino crosslinking agent.

The thickness of the organic film is within a range from 0.03 to 0.5 μm.

(6) Method of manufacturing semiconductor device

The method of manufacturing the semiconductor device of the presentinvention can be conducted, for example, by applying the above-describedresist pattern forming method in the manufacture of the semiconductordevice using a via-first dual damascene method.

For example, a base material obtained by laminating a first interlaminarinsulating layer, an etching stopper layer and a second interlaminarinsulating layer in sequence on a substrate is prepared. The first orsecond chemical amplification type positive resist composition of thepresent invention is applied on the base material and the coated basematerial is exposed through a mask pattern (selective exposure), therebyto make the exposed portion alkali-soluble, and then the exposed portionis removed (developed) with an alkali developing solution. Thus, apattern faithful to the mask pattern can be formed. The lower layer asthe portion with no resist pattern is etched to form via holes whichpenetrate the first interlaminar insulating layer, the etching stopperlayer and the second interlaminar insulating layer. Then, the first orsecond chemical amplification type positive resist compositioncontaining the components (A) and (B) is further applied and the coatedone is selectively exposed, thereby to make the exposed portionalkali-soluble. The exposed portion is removed with an alkali developingsolution to form a resist pattern and the lower layer with no resistpattern is etched to widen the groove width of the via holes formed onthe second interlaminar insulating layer, thereby to form wiringgrooves.

When an organic film is formed at the lower portion in the via holesformed in the first interlaminar insulating layer so as to ensure thesame level as that of the bottom portion of the wiring grooves formed atthe upper portion of the first interlaminer insulating layer and thechemical amplification type positive resist composition is applied,followed by exposure and further development in the same manner asdescribed above, and then the wiring grooves are etched, excess etchingcan be prevented by the organic film and, therefore, it is preferred.

In the case in which the organic film is formed in the via holes, theorganic film is removed and, finally, copper is embedded in the viaholes formed in the first interlaminar insulating layer and the wiringgrooves formed on the second interlaminar insulating layer on the firstinterlaminer insulating layer via the etching stopper layer, thereby tocomplete wiring, and thus a semiconductor device is obtained.

When using a base material obtained by laminating an insulating layerand a hard coat layer in sequence on a substrate, after forming viaholes which penetrate the insulating layer and the hard coat layer, anorganic film is preferably formed at the lower portion in the via holesin the same manner and a chemical amplification type positive resistcomposition is applied. The coated one is subjected to selectiveexposure and alkali-developed to form a resist pattern, and then etchingis conducted to widen the groove width of the upper portion of the viaholes, thereby to form wiring grooves. In the case in which an organicfilm is formed in the wiring grooves, the organic film is removed andcopper is embedded in these via holes and wiring grooves, and thus asemiconductor device can be manufactured.

EXAMPLES

The present invention will now be described in detail by way ofExamples. Various physical properties in the following Examples weredetermined in the following procedures.

(1) Retention Rate of Acid-Dissociable Dissolution Inhibiting Group

10 Parts by weight of the component (A) is dissolved in 90 parts byweight of propylene glycol monomethyl ether acetate to prepare asolution having a concentration of 10% by weight. To the resultingsolution, 10 parts by weight of hydrochloric acid having a concentrationof 10% by weight is added to prepare a uniform solution, which isstirred at 23° C. for 10 minutes, thereby to dissociate anacid-dissociable dissolution inhibiting group. The substitution rate ofthe acid-dissociable dissolution inhibiting group before and after theacid treatment is measured by a ¹³C-NMR method. The retention rate (ofthe acid-dissociable dissolution inhibiting group) is determined fromthe measured value by the equation described hereinabove.

(2) Sensitivity

To form wiring grooves at the upper portion of via holes of a basematerial provided with via holes described hereinafter, the basematerial was exposed to light through a predetermined photomask using aminifying projection exposure machine (Model FPA-3000EX3, manufacturedby Canon Co.) while increasing a dose by 1 mJ/cm² and subjected to PEB(post-exposure baking) at 110° C. for 60 seconds, followed bydevelopment in an aqueous 2.38 wt % solution of tetramethylammoniumhydroxide at 23° C. for 30 seconds, washing with water for 30 secondsand further drying. Then, the exposure time, which ensures a ratio of aresist pattern of 0.25 μm or 0.18 μm shown in Table 1 and Table 2 to aspace pattern of 1:1, was measured as the sensitivity. The measuredvalue was indicated by the amount of energy exposed (mJ/cm ²).

(3) Presence or Absence of Resist Residue on Via Holes

It was examined whether or not resist residue was produced on via holesby observing a SEM (scanning electron microscope) micrograph of a resistpattern with line-and-space (0.25 μm or 0.18 μm described in Table 1 andTable 2) obtained by the same operation as in (2) was observed. Sampleswhere no resist residue was observed were rated “◯”, samples whereslight resist residue was observed were rated “Δ”,and samples wheresevere resist residue was observed were rated “X”.

(4) Resolution

The limiting resolution of the line-and-space pattern obtained by thesame operation as in (2) was examined.

(5) Cross Sectional Profile of Resist Pattern

The cross sectional profile of the line-and-space pattern obtained in(3) was observed from the SEM micrograph. Samples which exhibit arectangular pattern or nearly rectangular pattern were rated “A”, whilesamples which exhibit a pattern having a round top portion (in the formof a curve) were rated “B”.

(Formation of Base Material and Via Holes)

After forming a first silicon oxide film (first interlaminar insulatinglayer having a dielectric constant of 2.7) on a silicon wafer by aplasma CVD method, a thin film (etching stopper layer) made of SiN wasprovided by a CVD method and a second silicon oxide film (secondinterlaminar insulating layer having a dielectric constant of 2.7) wasfurther provided thereon by the plasma CVD method to prepare a basematerial.

Then, via holes, which penetrate the first silicon oxide film, the SiNfilm and the second silicon oxide film, were formed.

Example 1

After forming a first silicon oxide film (first interlaminar insulatinglayer having a dielectric constant of 2.7) on a silicon wafer by theplasma CVD method, a thin film (etching stopper layer) made of SiN wasprovided by the CVD method and a second silicon oxide film (secondinterlaminar insulating layer having a dielectric constant of 2.7) wasfurther provided thereon by the plasma CVD method to prepare a basematerial.

Then, the following components (A) and (B) were prepared.

Component (A): 100 parts by weight of polyhydroxystyrene having aweight-average molecular weight of 8000 and a dispersion degree of 1.2in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a 1-isopropoxyethyl group

Component (B): 10 parts by weight of bis(isopropylsulfonyl)diazomethane

To these components (A) and (B), 0.40 parts by weight oftriisopropanolamine as an amine was added and they were dissolved in 500parts by weight of propylene glycol monomethyl etheracetate as asolvent, and then the resulting solution was filtered through a membranefilter (pore diameter: 0.2 μm) to prepare a coating solution of achemical amplification type positive resist composition.

The coating solution was applied on the base material prepared asdescribed above using a spinner and dried on a hot plate at 90° C. for60 seconds to form a resist film having a thickness of 0.53,μm, and thusa resist laminated material was prepared.

Example 2

The following components (A) and (B) were prepared.

Component (A): 100 parts by weight of polyhydroxystyrene having aweight-average molecular weight of 8000 and a dispersion degree of 1.2in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a 1-isopropoxyethyl group

Component (B): 10 parts by weight of bis(isopropylsulfonyl)diazomethane

To these components (A) and (B), 0.40 parts by weight oftriisopropanolamine as an amine was added and they were dissolved in 500parts by weight of propylene glycol monomethyl etheracetate as asolvent, and then the resulting solution was filtered through a membranefilter (pore diameter: 0.2 μm) to prepare a coating solution of achemical amplification type positive resist composition.

Then, an organic film (manufactured by Tokyo Ohka Kogyo Co., Ltd., underthe trade name of SWK-EX9) having a thickness of 110 nm was formed atthe lower portion in via holes of the base material prepared asdescribed above.

The coating solution was applied thereon using a spinner and dried on ahot plate at 90° C. for 60 seconds to form a resist film having athickness of 0.53 μm, and thus a resist laminated material was prepared.As described in (2), the resist laminated material was exposed to lightthrough a predetermined mask and subjected to PEB, and then a resistfilm of the exposed portion was removed with an alkali developingsolution to form a resist pattern. The second silicon oxide film formedthereunder was etched to form wiring grooves.

Physical properties of the resulting semiconductor device are shown inTable 1.

Example 3

In the same manner as in Example 2, except that the following components(A) and (B) are different from those in Example 2, a semiconductordevice was manufactured. Physical properties thereof are shown in Table1.

Component (A): 100 parts by weight of polyhydroxystyrene having aweight-average molecular weight of 8000 and a dispersion degree of 1.2in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a 1-ethoxyethyl group

Component (B): 15 parts by weight of bis(isopropylsulfonyl)diazomethane

Example 4

In the same manner as in Example 2, except that the following components(A) and (B) are different from those in Example 2, a semiconductordevice was manufactured. Physical properties thereof are shown in Table1.

Component (A): mixture of 50 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a 1-ethoxyethyl group and 50 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

Component (B): mixture of 5 parts by weight ofbis(isopropylsulfonyl)diazomethane and 10 parts by weight ofbis(tert-butylsulfonyl)diazomethane

Example 5

In the same manner as in Example 2, except that the following components(A) and (B) are different from those in Example 2, a semiconductordevice was manufactured. Physical properties thereof are shown in Table1.

Component (A): mixture of 50 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a 1-ethoxyethyl group and 50 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

Component (B): mixture of 5 parts by weight ofbis(isopropylsulfonyl)diazomethane, 10 parts by weight ofbis(tert-butylsulfonyl)diazomethane and 0.5 parts by weight ofbis(4-tertbutylphenyl)iodoniumtrifluoromethane sulfonate

Example 6

In the same manner as in Example 2, except that the following components(A) and (B) are different from those in Example 2, a semiconductordevice was manufactured. Physical properties thereof are shown in Table1.

Component (A): mixture of 50 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a 1-ethoxyethyl group and 50 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

Component (B): mixture of 5 parts by weight ofbis(isopropylsulfonyl)diazomethane, 10 parts by weight ofbis(tert-butylsulfonyl)diazomethane, 0.5 parts by weight ofbis(4-tertbutylphenyl)iodoniumtrifluoromethane sulfonate and 0.5 partsby weight of the compound represented by the chemical formula (1)

Comparative Example 1

In the same manner as in Example 2, except that the following was usedas the component (A), a semiconductor device was manufactured. Physicalproperties thereof are shown in Table 1.

Component (A): mixture of 30 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a tert-butoxycarbonyl group and 70 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

Comparative Example 2

In the same manner as in Example 2, except that the following was usedas the component (A), a semiconductor device was manufactured. Physicalproperties thereof are shown in Table 1.

Component (A): mixture of 30 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 30% of hydrogen atoms of existing hydroxyl groups aresubstituted with a tert-butyl group and 70 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

Comparative Example 3

In the same manner as in Example 2, except that the following was usedas the component (A), a semiconductor device was manufactured. Physicalproperties thereof are shown in Table 1.

Component (A): mixture of 20 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a tetrahydropyranyl group and 80 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

Comparative Example 4

In the same manner as in Example 2, except that the following was usedas the component (A), a semiconductor device was manufactured. Physicalproperties thereof are shown in Table 1.

Component (A): 100 parts by weight of polyhydroxystyrene having aweight-average molecular weight of 8000 and a dispersion degree of 1.2in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a tert-butoxycarbonyl group

Comparative Example 5

In the same manner as in Example 2, except that the following was usedas the component (A), a semiconductor device was manufactured. Physicalproperties thereof are shown in Table 1.

Component (A): mixture of 50 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a tetrahydropyranyl group and 50 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

TABLE 1 Retention rate (%) of acid- dissociable Presence or dissolutionSensitivity absence of Resolution inhibiting agent (mJ/cm²) resistresidue (μm) Examples 2 29 42 (0.25 μm) ◯ 0.18 3 29 45 (0.25 μm) ◯ 0.184 29 42 (0.25 μm) ◯ 0.18 5 29 39 (0.18 μm) ◯ 0.15 6 29 35 (0.18 μm) ◯0.15 Comparative Examples 1 100 41 (0.25 μm) Δ 0.18 2 100 40 (0.25 μm) X0.18 3 57 45 (0.25 μm) Δ 0.18 4 100 not resolvable impossible to not(0.25 μm) evaluate resolvable 5 57 52 (0.25 μm) X 0.20

In Table 1, in the case in which the component (A) is a mixture of twokinds and has two kinds of acid-dissociable dissolution inhibitinggroups, a higher retention rate of the acid-dissolution inhibiting groupwas described.

As is apparent from the results shown in the table, no resist residuewas observed in the Examples using the component (A) in which theretention rate of the acid-dissolution inhibiting group is 40% or lessof the present invention and thus the present invention were made clear.In contrast, resist residue was observed in the Comparative Examples,though there was some difference.

Example 7

After forming a first silicon oxide film (first interlaminar insulatinglayer having a dielectric constant of 2.7) on a silicon wafer by theplasma CVD method, a thin film (etching stopper layer) made of SiN wasprovided by the CVD method and a second silicon oxide film (secondinterlaminar insulating layer having a dielectric constant of 2.7) wasfurther provided thereon by the plasma CVD method to prepare a basematerial.

Then, the following components (A) and (B) were prepared.

Component (A): mixture of 50 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a 1-ethoxyethyl group and 50 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

Component (B): mixture of 5 parts by weight ofbis(isopropylsulfonyl)diazomethane, 10 parts by weight ofbis(tert-butylsulfonyl)diazomethane, 0.5 parts by weight ofbis(4-tertbutylphenyl)iodoniumtrifluoromethane sulfonate and 0.5 partsby weight of the compound represented by the chemical formula (1)

To these components (A) and (B), 0.40 parts by weight oftriisopropanolamine as an amine was added and they were dissolved in 500parts by weight of propylene glycol monomethyl etheracetate as asolvent, and then the resulting solution was filtered through a membranefilter (pore diameter: 0.2 μm) to prepare a coating solution of achemical amplification type positive resist composition.

The coating solution was applied on the base material prepared asdescribed above using a spinner and dried on a hot plate at 90° C. for60 seconds to form a resist film having a thickness of 0.53 μm, and thusa resist laminated material was prepared.

Example 8

The following components (A) and (B) were prepared.

Component (A): mixture of 50 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a 1-ethoxyethyl group and 50 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

Component (B): mixture of 5 parts by weight ofbis(isopropylsulfonyl)diazomethane, 10 parts by weight ofbis(tert-butylsulfonyl)diazomethane, 0.5 parts by weight ofbis(4-tertbutylphenyl)iodoniumtrifluoromethane sulfonate and 0.5 partsby weight of the compound represented by the chemical formula (1)

To these components (A) and (B), 0.40 parts by weight oftriisopropanolamine as an amine was added and they were dissolved in 500parts by weight of propylene glycol monomethyl etheracetate as asolvent, and then the resulting solution was filtered through a membranefilter (pore diameter: 0.2 μm) to prepare a coating solution of achemical amplification type positive resist composition.

Then, an organic film (manufactured by Tokyo Ohka Kogyo Co., Ltd. underthe trade name of SWK-EX9) having a thickness of 110 nm was formed atthe lower portion in via holes of the base material prepared asdescribed above.

The coating solution was applied thereon using a spinner and dried on ahot plate at 90° C. for 60 seconds to form a resist film having athickness of 0.53 μm, and thus a resist laminated material was prepared.As described in (2), the resist laminated material was exposed to lightthrough a predetermined mask and subjected to PEB, and then a resistfilm of the exposed portion was removed with an alkali developingsolution to form a resist pattern. The second silicon oxide film formedthereunder was etched to form wiring grooves.

Physical properties of the resulting semiconductor device are shown inTable 2.

Example 9

In the same manner as in Example 8, except that the following components(A) and (B) are used, a semiconductor device was manufactured. Physicalproperties thereof are shown in Table 2.

Component (A): mixture of 50 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a 1-ethoxyethyl group and 50 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

Component (B): mixture of 5 parts by weight ofbis(isopropylsulfonyl)diazomethane, 10 parts by weight ofbis(tert-butylsulfonyl)diazomethane and 0.5 parts by weight ofbis(4-tertbutylphenyl)iodoniumtrifluoromethane sulfonate

Example 10

In the same manner as in Example 8, except that the following components(A) and (B) are used, a semiconductor device was manufactured. Physicalproperties thereof are shown in Table 2.

Component (A): mixture of 50 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a 1-ethoxyethyl group and 50 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

Component (B): mixture of 5 parts by weight ofbis(isopropylsulfonyl)diazomethane and 10 parts by weight ofbis(tert-butylsulfonyl)diazomethane

Example 11

In the same manner as in Example 8, except that the following components(A) and (B) are used, a semiconductor device was manufactured. Physicalproperties thereof are shown in Table 2.

Component (A): 100 parts by weight of polyhydroxystyrene having aweight-average molecular weight of 8000 and a dispersion degree of 1.2in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a 1-ethoxyethyl group

Component (B): 15 parts by weight of bis(isopropylsulfonyl)diazomethane

Comparative Example 6

In the same manner as in Example 11, except that the following was usedas the component (A), a semiconductor device was manufactured. Physicalproperties thereof are shown in Table 2.

Component (A): mixture of 30 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a tert-butoxycarbonyl group and 70 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

Comparative Example 7

In the same manner as in Example 11, except that the following was usedas the component (A), a semiconductor device was manufactured. Physicalproperties thereof are shown in Table 2.

Component (A): mixture of 30 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 30% of hydrogen atoms of existing hydroxyl groups aresubstituted with a tert-butyl group and 70 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

Comparative Example 8

In the same manner as in Example 11, except that the following was usedas the component (A), a semiconductor device was manufactured. Physicalproperties thereof are shown in Table 2.

Component (A): mixture of 20 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a tetrahydropyranyl group and 80 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

Comparative Example 9

In the same manner as in Example 11, except that the following was usedas the component (A), a semiconductor device was manufactured. Physicalproperties thereof are shown in Table 2.

Component (A): 100 parts by weight of polyhydroxystyrene having aweight-average molecular weight of 8000 and a dispersion degree of 1.2in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a tert-butoxycarbonyl group

Comparative Example 10

In the same manner as in Example 11, except that the following was usedas the component (A), a semiconductor device was manufactured. Physicalproperties thereof are shown in Table 2.

Component (A): mixture of 50 parts by weight of polyhydroxystyrenehaving a weight-average molecular weight of 8000 and a dispersion degreeof 1.2 in which 35% of hydrogen atoms of existing hydroxyl groups aresubstituted with a tetrahydropyranyl group and 50 parts by weight ofpolyhydroxystyrene having a weight-average molecular weight of 8000 anda dispersion degree of 1.2 in which 35% of hydrogen atoms of existinghydroxyl groups are substituted with a 1-isopropoxyethyl group

TABLE 2 Acid-dissociable Presence or Cross sectional dissolutionSensitivity absence of resist Resolution Retention profile of resistinhibiting group (mJ/cm²) residue (μm) rate (%) pattern Example 81-ethoxyethyl group 35 ◯ 0.15 29 A 1-isopropoxyethyl group (0.18 μm)Example 9 1-ethoxyethyl group 39 ◯ 0.15 29 A 1-isopropoxyethyl group(0.18 μm) Example 10 1-ethoxyethyl group 42 ◯ 0.18 29 A1-isopropoxyethyl group (0.25 μm) Example 11 1-ethoxyethyl group 45 ◯0.18 29 B (0.25 μm) Comparative tert-butoxycarbonyl group 41 Δ 0.18 100A Example 6 1-isopropoxyethyl group (0.25 μm) Comparative tert-butylgroup 40 X 0.18 100 A Example 7 1-isopropoxyethyl group (0.25 μm)Comparative tetrahydropyranyl group 45 Δ 0.18 57 A Example 81-isopropoxyethyl group (0.25 μm) Comparative tert-butoxycarbonyl groupnot resolvable impossible to not 100 — Example 9 (0.25 μm) evaluateresolvable Comparative tetrahydropyranyl group 52 X 0.20 57 A Example 101-isopropoxyethyl group (0.25 μm)

As is apparent from the results shown in Table 2, Examples 8 to 10 usingtwo or more kinds of mutually different straight-chain or branched loweralkoxy-alkyl groups as the component (A) are superior in sensitivity andcross sectional profile of the resist pattern to Example 11 and are alsosuperior in sensitivity, resolution, presence of absence of resistresidue and cross sectional profile of the resist pattern to theComparative Examples.

INDUSTRIAL APPLICABILITY

According to the present invention, there can be provided a chemicalamplification type positive resist composition which can give ahigh-resolution resist pattern capable of coping with fine patternrequired to the manufacture of semiconductor devices by a via-first dualdamascene method without producing resist residue, a resist patternforming method, and a method of manufacturing a semiconductor deviceusing the same.

1. A chemical amplification type positive resist composition comprisingthe following components (A) and (B): (A) polyhydroxystyrene in which atleast a portion of hydrogen atoms of hydroxyl groups are substitutedwith a lower alkoxy-alkyl group having a straight-chain or branchedalkoxy group and the lower alkoxy-alkyl group is eliminated by an actionof an acid, and the solubility in an alkali solution of the polyhydroxystylene increases when elimination occurs, and (B) a component capableof generating an acid by irradiation with radiation, wherein two or morekinds of mutually different lower alkoxy-alkyl groups are used as thelower alkoxy-alkyl group of the component (A), wherein at least one kindamong the lower alkoxy-alkyl groups is a lower alkoxy-alkyl group havinga straight-chain alkoxy group and at least one kind among other loweralkoxy-alkyl groups is a lower alkoxy-alkyl group having a branchedalkoxy group, and wherein the component (B) comprisesbisalkylsulfonyldiazomethane as a main component, and comprises an oniumsalt in an amount of 2 to 5% by weight based on thebisalkylsulfonyldiazomethane.
 2. The chemical amplification typepositive resist composition according to claim 1, wherein thestraight-chain lower alkoxy-alkyl groups are one, two or more kindsselected from the group consisting of 1-ethoxyethyl group,1-methoxy-1-methylethyl group, 1-methoxypropyl group and 1-n-butoxyethylgroup, and the branched lower alkoxy-alkyl groups are one, two or morekinds selected from the group consisting of 1-isopropoxyethyl group,1-isobutoxyethyl group and 1-sec-butoxyethyl group.
 3. The chemicalamplification type positive resist composition according to claim 1,wherein the component (A) comprises: (A1) polyhydroxystyrene in which atleast a portion of hydrogen atoms of hydroxyl groups are substitutedwith a 1-straight-chain alkoxy-alkyl group, and (A2) polyhydroxystyrenein which at least a portion of hydrogen atoms of hydroxyl groups aresubstituted with a 1-branched alkoxy-alkyl group.
 4. The chemicalamplification type positive resist composition according to claim 3,wherein the component (A) comprises: (A1′) polyhydroxystyrene in which10 to 60% of hydrogen atoms of hydroxyl groups of polyhydroxystyrenehaving a weight-average molecular weight of 3000 to 30000 and dispersiondegree (number-average molecular weight/weight-average molecular weight)of 1.0 to 6.0 are substituted with a 1-straight-chain alkoxy-alkylgroup, and (A2′) polyhydroxystyrene in which 10 to 60% of hydrogen atomsof hydroxyl groups of polyhydroxystyrene having a weight-averagemolecular weight of 3000 to 30000 and dispersion degree (number-averagemolecular weight/weight-average molecular weight) of 1.0 to 6.0 aresubstituted with a 1-branched alkoxy-alkyl group.
 5. The chemicalamplification type positive resist composition according to claim 3,wherein the component (A) is a mixture obtained by mixing the component(A1) with the component (A2) in a weight ratio within a range from 1:9to 9:1.
 6. The chemical amplification type positive resist compositionaccording to claim 1, wherein the bisalkylsulfonyldiazomethane isbis(isopropylsulfonyl)diazomethane, bis(tert-butylsulfonyl)diazomethaneor a mixture thereof.
 7. The chemical amplification type positive resistcomposition according to claim 1, wherein a tertiary aliphatic amine ismixed with the chemical amplification type positive resist composition.8. A resist laminated material comprising a base material obtained bylaminating a first interlaminar insulating film layer, an etchingstopper layer and a second interlaminar insulating layer in sequence,and a coating layer of the chemical amplification type positive resistcomposition of claim 1 provided on the base material.
 9. A resistpattern forming method, which comprises applying a chemicalamplification type positive resist composition on a base material andsubjecting the coated base material to selective exposure anddevelopment in sequence to form a resist pattern, wherein the chemicalamplification type positive resist composition is a chemicalamplification type positive resist composition of claim
 1. 10. Theresist pattern forming method according to claim 9, wherein the basematerial is obtained by laminating a first interlaminar insulatinglayer, an etching stopper layer and a second interlaminar insulatinglayer in sequence on a substrate.
 11. The resist pattern forming methodaccording to claim 10, wherein either or both of the first interlaminarinsulating layer and the second interlaminar insulating layer aresilicon oxide layers having a dielectric constant of 3.0 or less. 12.The resist pattern forming method according to claim 10, wherein theetching stopper layer is formed of silicon nitride, silicon carbide ortantalum nitride.
 13. The resist pattern forming method according toclaim 9, wherein the base material is obtained by laminating aninsulating layer and a hard mask layer in sequence on a substrate. 14.The resist pattern forming method according to claim 13, wherein theinsulating layer is a silicon oxide layer having a dielectric constantof 3.0 or less.
 15. A method of manufacturing a semiconductor deviceusing a via-first dual damascene method of forming via holes on a basematerial and forming wiring grooves at the upper portion, whichcomprises forming at least the wiring grooves by the resist patternforming method of claim
 9. 16. The method of manufacturing thesemiconductor device according to claim 15, wherein an organic film isformed at the lower portion of the via holes and then the wiring groovesare formed by the resist pattern forming method of claim
 9. 17. A methodof manufacturing a semiconductive device by a via-first dual damascenemethod comprising applying a chemical amplification type positive resistcomposition according to claim 1.